The primary area of statistical expertise in the Qian-Li Xue Lab is the development and application of statistical methods for: (1) handling the truncation of information on underlying or unobservable outcomes (e.g., disability) as a result of screening, (2) missing data, including outcome (e.g., frailty) censoring by a competing risk (e.g., mortality) and (3) trajectory analysis of multivariate outcomes. Other areas of methodologic research interests include multivariate, latent variable models. In Women's Health and Aging Studies, we have closely collaborated with scientific investigators on the design and analysis of longitudinal data relating biomarkers of inflammation, hormonal dysregulation and micronutrient deficiencies to the development and progression of frailty and disability, as well as characterizing the natural history of change in cognitive and physical function over time.